Hello! Thanks for reading and for the reply!
I spent a little time reading about the Presonus. It seems like a nice little audio interface! The headphone jack on the back has its own amp attached to it, so you shouldn’t need to buy a new one, and from what I’ve been able to gather, it should have more than enough power for the 80ohm 770s. The 770’s aren’t the loudest headphones in the world, but that jack should provide enough oomph.
A lot of folks buy audio interfaces instead of pure DAC/amp units because they tend to offer slightly better value for the money beyond a certain price point. And they of course offer more functionality thanks to their recording capabilities.
If you’ve been listening through that headphone port on the back and you still find the performance lacking…that doesn’t leave you with many options, I’m afraid. You could try the headphones with a different source and see if that helps, on the off chance that your Presonus headphone output isn’t working correctly. You’ve already been using them for 9 days, so brain adjustment probably isn’t a factor, unless your previous headphones were vastly different from the 770’s sound signature. It’s possible that you just don’t like them, subjectively.
Something might also be wrong with the drivers. Beyerdynamic has pretty good build quality, but issues do arise here and there. Have you asked a friend to listen and see what they think?
I’m sorry I don’t have better news or an idea for something that would suddenly cure your issues! But I personally wouldn’t dive down the tech rabbit hole and buy more amplification gear. Did you buy the headphones from a place with a good return policy?
I hope that helps you out in some way. Thanks again for reading!